import sys
import pygame
import os

pygame.init()
size = width, height = 640, 480
screen = pygame.display.set_mode(size)
color = (0, 0, 0)

path = os.getcwd()
print('path', path)
filepath = os.path.join(path, "chapter/13/ball.png")
print('filepath', filepath)
ball = pygame.image.load(filepath)
ballrect = ball.get_rect()

speed = [5, 5]
clock = pygame.time.Clock() # 设置时钟
# 执行死循环，确保窗口一直显示
while True:
  clock.tick(60)    # 每秒执行60次
  # 检查事件
  for event in pygame.event.get():
      if event.type == pygame.QUIT:
          pygame.quit()
          sys.exit()

  ballrect = ballrect.move(speed) # 移动小球
  # 碰到左右边缘
  if ballrect.left < 0 or ballrect.right > width:
      speed[0] = -speed[0]

  # 碰到上下边缘
  if ballrect.top < 0 or ballrect.bottom > height:
      speed[1] = -speed[1]

  screen.fill(color)            # 填充颜色 RGB
  screen.blit(ball, ballrect)   # 将图片画到窗口上
  pygame.display.flip()         # 更新全部显示
